The invention relates to a housing with a bore for an internal-combustion engine. The bore is formed of at least two mutually spaced bore sections and, in particular, is a bearing tunnel in a crankcase or a cylinder head of the internal-combustion engine.
Concerning the technical environment, reference is made, for example, to German Published Patent Application DE 10 2010 006 188 A1. From DE 10 2010 006 188 A1, a grinding system and a process for manufacturing a crankcase are known. The grinding system is suitable for the machining of a plurality of crankshaft bearing bores for roller bearings of a crankshaft mounted in the crankcase. In this case, the grinding system has a rotatorily drivable tool shaft, which carries a plurality of machining units arranged in a mutually axially spaced manner, whose number corresponds to the number of crankshaft bearing bores present at the crankcase. Each machining unit arranged on the tool shaft has at least one grinding wheel. An axial distance between the grinding wheels of two adjacent machining units corresponds to a distance between two adjacent crankshaft bearing bores. So that a cylindrical grinding precision is achieved that is as high as possible, the grinding tool is supported by a separate counterbearing on the side of the housing facing away from the drive of the tool.
Furthermore, from German Published Patent Application DE 10 2009 051 285 A1, a process and a honing tool for manufacturing at least one bearing bore, as well as an internal-combustion engine having at least one honed bearing bore, are known. Among others, a process is also disclosed for manufacturing at least one bearing bore in the internal-combustion engine, particularly for a crankshaft or a camshaft, by means of a honing tool, which is moved parallel to a bore axis of the bearing bore axially and rotating about a tool axis. It is suggested to produce, in a non-loaded state of the bearing bore, by form-honing the interior surface of the bearing bore, a starting shape of the bearing bore which is asymmetrical in such a fashion that, in an operating state, the bearing bore has a symmetrical operating shape that deviates from the initial shape. Furthermore, a honing tool is disclosed for producing at least one bearing bore. In order to achieve the best-possible surface quality, the honing tool is also disposed on a counterbearing on its side facing away from the tool drive, which counterbearing is arranged outside the internal-combustion engine.
Furthermore, from German Published Patent Application DE 10 2010 010 901 A1, on which the present invention is based, a process and a system are known for finish-machining a crankshaft bearing bore. In the process for finish-machining, particularly for finish-machining a crankshaft bearing bore in a cylinder crankcase of an internal-combustion engine, starting from a prepared bore, a finish-machined bore is produced which has a defined finished size, a defined desired structure of the interior bore surface and a defined position of the bore axis. The process is characterized by at least one power honing operation in which, while a honing tool is used, by honing the bore, a removal of material of at least 0.5 mm is generated relative to the diameter of the bore. The power honing operation is carried out as an axial-position-correcting honing operation such that, as a result of the power honing operation, a displacement of the bore axis takes place in the direction of the desired position. In order to achieve a quality of the honed surface that is as high as possible, a workpiece mounting device is provided for the workpiece and, in addition, a counterbearing is provided on the side of the workpiece mounting device facing away from the honing spindle, for the rotatable bearing of the honing tool, in which case the counterbearing can preferably be moved along with the honing tool during the lifting movement of the honing tool, i.e., its position can be changed in the axial direction.
Even if the above-mentioned systems and processes have no significant disadvantages, it is desirable to reduce the space requirement for a machining of a housing according to the above-mentioned type.
This and other objects are achieved by providing a housing for an internal combustion engine, the housing having a bore formed of at least two mutually spaced bore sections. The bore, in particular, is a bearing tunnel in a crankcase or a cylinder head of the internal-combustion engine. For machining the bore, a rotating cutting tool is provided which, on one side, can be inserted in the bore by axial displacement and, on the other side of the bore, is radially supported by a counterbearing for the tool. The counterbearing is in one piece with the housing.
According to the invention, by way of the counterbearing, which is in one piece with the crankcase—a guide bore, as it were—, the tool can be guided for the machining of the bore in the housing, for example, a crankshaft bearing bore. Thus, a swerving of the tool that differs over the service life of the tool, for example, as a result of different materials, will also no longer be possible. Advantageously, the cycle time of the machining can be reduced by up to 25%, while the concentricity of the finished bore is excellent.
According to a further development, the counterbearing is connected with the housing in a force-locking or form-fitting and/or bonded manner. This may take place, for example, in that the counterbearing is produced together with the housing in one casting process. In other embodiments, it may, for example, also be screwed on, welded on, or soldered on.
In a further embodiment, the counterbearing is an extension of, particularly, a crankshaft bearing.
Particularly preferably, the counterbearing is used as a bore for a radial shaft sealing ring. This provides best-possible concentricity between the bearing and the radial shaft sealing ring, which has a positive effect on the permanent tightness.
According to a still further development, the inside diameter of the counterbearing is smaller than the bore diameter of the bore sections.
The process according to the invention can be used not only for a crankshaft bearing tunnel but also, for example, for a camshaft bearing tunnel and/or an eccentric shaft bearing tunnel.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawing.